Many automotive vehicles are equipped with an automatic start/stop system, which automatically shuts down and restarts the engine of a vehicle to reduce fuel consumption of the vehicle under certain conditions. In operation, the internal combustion engine can be stopped, i.e. switched off, automatically by the automatic start/stop system if no propulsion is required, for example by idling at a traffic light, and can be restarted if the driver calls for power again.
One type of start/stop system is known as a rolling start/stop. A rolling start/stop system involves stopping the internal combustion engine when the vehicle is moving and decelerating. When power from the engine is required, e.g., the driver releases the brakes, the engine is automatically restarted. The engine may also be automatically started in response to other conditions such as battery state of charge or loads on the electrical system. These engine auto stops may improve fuel economy and reduce emissions by reducing engine idle time and thus fuel consumption for the drive cycle. However, a rolling start/stop in a vehicle with an automatic transmission connected to the drivetrain via a conventional torque converter may result in objectionable noise, vibration, and harshness (NVH) or drivability. One strategy to mitigate these effects is to automatically shift the transmission into neutral, although this requires rapid reengagement when power is demanded and may result in a shift bump that is also objectionable to some occupants.